The need for compounds for use in propellant compositions to prevent catalysis of the urethane reaction by cure inducing materials such as Catocene, iron oxide, ferric fluoride, etc. without interfering with the function of the cure catalyst triphenylbismuthine was met with the employment of about 0.02 to about 0.03 weight percent of dicarboxylic acids (e.g. maleic and oxalic or anhydrides of the same). Extended potlife in diisocyanate cured polymer systems, such as hydroxyl-terminated polybutadienes, polyesters, etc. is achieved with typical potlife changes being increased from 0-2 hours to 12-15 hours. The use of triphenylbismuthine (TPB) promotes the urethane reaction as well; therefore, the use of the dicarboxylic acid provides other advantages which enables TPB to be used even with the more reactive isocyanates since potlife is extended and undesirable side reactions are reduced as well. A commonly assigned U.S. Pat. No. 4,597,811, titled: "Prevention of Unwanted Cure Catalysis in Isocyanate Cured Binders", which was issued to Marjorie E. Ducote on July 1, 1986, provides additional teachings of cure catalysis behavior of TPB and the dicarboxylic acids, including the discovery of the additional benefits achieved from premixing the catalyst system with the diisocyanate curing agent before they are added to the propellant slurry. This behavior was evidenced in the use of maleic anhydride (MAN) particularly where maleic acid (MAC) is present as a contaminant in the MAN and where MAC is produced by hydrolysis of MAN.